The present invention relates to a fuel injector electromagnetic metering valve.
The metering valves of fuel injectors generally comprise a control chamber with a drain conduit normally closed by a shutter which, in known metering valves, is normally closed by the armature of an electromagnet, and is released to open the conduit by energizing the electromagnet so as to move the armature towards the core of the electromagnet.
The electromagnets of known metering valves generally present two coaxial pole pieces defining a seat for a cylindrical coil, while the armature is in the form of a disk designed to close the magnetic circuit of the core and the diameter of which is normally substantially larger than the outside diameter of the core coil seat. The armature is normally guided by a sleeve fitted to the injector body by means of a threaded ring nut and into .which the armature is subsequently inserted.
A major drawback of metering valves of the aforementioned type is that they fail to enable the pilot valve assembly to be checked and/or tested separately prior to final assembly.